High lift surface systems of aircraft are used to increase lift during takeoff or landing; they typically comprise landing flaps, leading-edge flaps or wing regions with a continuously variable profile or similar arrangements by means of which the wing profile can be changed and/or enlarged with a view to augmenting lift. In many civil aircraft and also in military transport aircraft such high lift surfaces are driven by a central drive unit that is connected, by way of a rotary shaft arrangement that typically extends in the spanwise direction, to local mechanical final control elements provided on the high lift surfaces. The local final control elements can comprise spindles or crank mechanisms or similar actuation devices. In most cases several such high lift surfaces are arranged along the rotary shaft arrangement. Typically a first such rotary shaft arrangement extends along the front region of the wing profile, thus serving to actuate leading-edge flaps provided in this location, while a second rotary shaft arrangement extends along the rear region of the wing, thus serving to drive the landing flaps provided in this location. If during extension or retraction of the high lift surfaces a blockage occurs within the rotary shaft arrangement or within the final control elements associated with the high lift surfaces, between the location of the blockage and the drive unit the rotary shaft arrangement is subjected to torsional stress by the drive motor until the stall torque has been reached. This results in substantial torsional loads that according to the state of the art until now could only be reduced after the end of the flight and after carrying out corresponding repair work. Until repairs can be effected, the rotary shaft system remains in the stressed state, loaded with the maximum motor moment. As a result of the substantial torsional moment of the stressed shaft arrangement in the case of a blockage, the rotary shaft system is thus subjected to very considerable mechanical stress between the drive motor and the location of the blockage, which mechanical stress is still further increased if in addition bending moments and tensile-/compressive loads are introduced into the rotary shaft system as a result of wing bending, landing shocks or the like. The individual elements of the rotary shaft system have to be dimensioned to provide the corresponding strength, with the safety factors—which have been calculated taking into account the possibility of extended times under load—limiting the options of optimising the weight of the shafts.